This invention relates to a measurement method and apparatus and, more particularly, to the measurement, interpolation and plotting of elevations of points located on drawings.
In architecture and civil engineering it is routine practice, from known data recorded on drawings, to plot contour lines and to estimate elevation values at specific locations and conversely to estimate locations of specific elevation values.
While there are existing techniques that aid in the interpolation process by using standard mechanical drawing equipmant such as triangles and scaled rulers, the various pieces of equipment used are not coordinated with the process as a whole or with each other. It is common pracice, in each individual case of interpolation, first, to make a mathematical assessment of the whole numbers and fractions that are involved, second, to construct a temporary line on the drawing having the proportional divisions thus determined and, finally, to transfer those divisions to the line for which the interpolation is intended. To do this it is necessary to adopt the temporary line length to the length of the line to be interpolated by forming similar triangles with miscellaneous drafting equipment available.
Accordingly, it is the object of this invention to facilitate direct interpolation between points on a drawing, either isolated or on contour lines.
A related object is to facilitate direct interpolation to determine elevation values at known locations or conversely of locations of known elevation values.
Another object of the invention is to facilitate interpolation between two points by direct readings on, or direct transfer from, standard, graphic, interpolation, scale models.
A related object is to realize an instrument that minimizes the time necessary for the interpolation process.
Another related object is to realize an instrument that minimizes the chances of inaccuracies and errors made during the interpolation process.
A further object of the invention is to render unnecessary a mathematical assessment of the whole numbers and fractions for each individual case of interpolation by substituting therefor a selection chart for, and the combined use of, a bank of standard, graphic, interpolation, scale models.
Still another object of the invention is to render unnecessary the construction of a temporary line appropriately proportioned but of random length for each individual interpolation by substituting therefor an appropriate line from a bank of standard, graphic, interpolation, scale models.
Yet another object of the invention is realizing a pocket size intrument capable of all interpolations between points up to three and a half inches apart.
Another related object is realization of a convenient instrument size by the use of the minimum number of graphic scales achieved by employing them in both a primary and alternate application.